This invention relates to structure and methodology regarding the installing, removing, and replacing of a wearable/replaceable tool relative to an associated tool carrier. A preferred and best-mode embodiment of the invention is illustrated and described herein in the context of a perimeter-mount shear cutting tool and a power-driven, rotary tool carrier, which is designed removably to receive such a tool.
The invention, which, as will be seen, possesses utility in many environments and applications, has emerged specifically in the hostile world of rotary, impact, shear-type material shredders, such as tire shredders, wherein issues, such as frequent tool breakage, and short tool life-cycles, continue to plague shredder operators with costly and extended down-times linked to worn or broken-tool issues.
Appropriate tool alignment in relation to its associated tool carrier is also often an issue requiring attention.
Rapid tool wear in the illustrative tire-shredder environment, especially in such an environment where the tires to be shredded include steel-belted tires, is normal and expected, but frequent tool breakage should not be so. Both wear and breakage in this setting are usually attributed chiefly to tool engagement with the steel-belting structure included in most, if not all, modern tires.
Regarding the issue of tool wear, a conventional, heavy-duty, rotary, shear-type shredder, such as the above-mentioned tire shredder, may possess up to several hundreds of carrier-mounted tools. Normally, these tools are plural-bolt (typically three) anchored to the perimeter of a rotary carrier, with the associated shredder possessing a large plurality of such carriers. Such carriers are laterally “stacked” adjacent one another on a power-driven support shaft. U.S. Pat. Nos. 3,931,935, 4,374,573, 4,854,508, and U.S. Patent Application Publication No. 2006/0086854 A1, the contents of which are referred to herein for background information purposes, illustrate this conventional environment.
In this environment, tool manufacturers routinely suggest, with respect to when a shredder is shut down to deal, for example, simply with a tool-wear situation involving one, or several, tools, that all tools be replaced at that time. Such tool replacement is a very large time commitment, especially where, for each tool, and as is frequently the case, plural anchoring bolts must be removed and later installed for each removed and replaced tool.
Tool breakage, which is normally linked to anchoring-bolt breakage, often results from the truth about, rather than the belief in, the robustness of the usual plural-bolt anchoring paradigm. A tool of the type described above is not really held in place at any moment in time by the combined strengths of the plural (typically three) normally employed anchoring bolts, i.e., bolts which can be counted upon collectively to hold until all three simultaneously fracture to define a tool break. Rather, such a tool is only anchored effectively by the “one-bolt-at-a-time” condition, wherein breaking-point is defined, at every moment in time, by merely the strength of a single bolt. When a first bolt to break does so, and this will always be the case (in the sense of there being just one tool-anchoring bolt which first fails), another one of the tool-anchoring, remaining, intact bolts will, each as a singularity, be next to fail, and so on, until a related tool is no longer secured to a carrier. Catastrophic tool breakage, per se, quickly follows.
Another important consideration is tool alignment on a carrier. Here, an issue which is associated with the usual, plural-bolt anchoring approach of the prior art relates to the necessarily required tolerance precision (a) of the anchoring bolt shanks, (b) of the provided, bolt-receiving throughbores included in prior art tools, and (c) of the needed bolt-thread receiving threaded wells formed for each tool on the perimeter of a carrier. Three general “regions” of such tolerance precision are thus linked to each and every usual prior art tool of the type mentioned above, and this condition presents a large challenge not only in relation to initial tool-to-carrier installation, but also in relation to every tool removal, and return or replacement, operation. Regarding the latter activity, precision-tolerance alignment issues surface predictively when “returned” bolts do not return to the exact locations from which they were removed, and certainly also whenever a new tool, and/or a new bolt, is/are installed to replace the old tool and/or an old bolt.
The present invention addresses all of the above-mentioned issues in practical, extremely effective, remarkably simple, and inexpensive ways.
Stated simply, and with more specificity, the invention features a heat-cool, shrink-bind tool/carrier mounting which is characterized (a) by the absence of any independent tool-to-carrier mounting hardware, per se, (b) by the attendant, reduced cost and material simplicity to which this absence leads, (c) by a fastening robustness which essentially obviates the likelihood of tool breakage, and which also, in the bargain, furnishes tool anchoring security and stability far surpassing those aspects of prior art approaches, (d) by precision, tool/carrier, operative alignment which is superior to that which is attainable in the prior art, and (e) by enabled styles of tool-carrier connection and disconnection that are remarkably quickly and easily performable.
These and other features and advantages which are offered by the present invention will become more fully apparent as the detailed description of the invention which now follows is read in conjunction with the accompanying drawings.